Plasmonic MXene-based nanocomposites exhibiting photothermal therapeutic effects with lower acute toxicity than pure MXene

Purpose: Here, we fabricated two plasmonic 2D Ti₃C₂T_x-based nanocomposites (Au/MXene and Au/Fe₃O₄/MXene) with similarly high anti-cancer photothermal therapy (PTT) capabilities, but with less in vivo toxicity than a pure MXene. Methods: Au/MXene was synthesized by in situ reduction of tetrachloroauric acid using NaBH₄ on Ti₃C₂T_x flakes. For targeted PTT, magnetic Au/Fe₃O₄/MXene was synthesized via a reaction between freshly prepared magnetite Fe₃O₄ NPs and MXene solution, followed by in situ integration of gold nanoparticles (AuNPs). Results: Morphological characterization by XRD, SEM, and TEM revealed the successful synthesis of Au/MXene and Au/Fe₃O₄/MXene. Both new composites exhibited a significant in vitro dose-dependent PTT effect against human breast cancer cells MCF7. Interestingly, in vivo acute toxicity assays using zebrafish embryos indicated that Au/MXene and Au/Fe₃ O₄/MXene had less embryonic mortality (LC₅₀ ≫ 1000 μg/mL) than pure MXene (LC₅₀=257.46 μg/mL). Conclusion: Our new Au/MXene and Au/Fe₃O₄/MXene nanocomposites could be safer and more suitable than the pure MXene for biomedical applications, especially when targeted PTT is warranted.